1. Field of the Invention
The present invention relates to an electrophotographic image recording apparatus, and more particularly to an electrophotographic image recording apparatus of a type employed with both an image reading portion and an image recording portion.
2. Description of the Related Art
There has been conventionally proposed an electrophotographic image recording apparatus, such as a digital image copying machine, of a type which is employed with both an image reading portion and an image recording portion.
As shown in FIG. 1, the image reading portion 81 of this apparatus generally includes an image reading head 84 constructed from a combination of a light source 82 such as a rod-shaped fluorescent lamp and an image receiving element 80 such as a contact type image sensor or a CCD image sensor. The fluorescent lamp 82 extends in a main scanning direction A which extends orthogonal to the sheet of drawing of FIG. 1. The fluorescent lamp 82 emits a light beam in a direction toward an original stand 86. The light beam passes through the original stand 86 and reflects off an original 88 located on the original stand 86 so as to bear thereon a line image of the original. The line image-bearing light then travels to the image receiving element 80. The image receiving element 80 thus receiving the optical line image converts it into electrical signals.
The original stand 86 is conveyed in an auxiliary scanning direction B orthogonal to the main scanning direction A so that all the line images on the original 88 are sequentially picked up to be converted into electrical image signals. The electrical image signals are then fed to an image recording portion 91.
The image recording portion 91 includes a light scanning unit 90 and a photosensitive drum 92. The light scanning unit 90 includes: a spot light beam source 94 for intermittently emitting a spot light beam in accordance with the electrical image signals; and a light scanning mechanism 96 for receiving the light beam from the light source 94 and for scanningly guiding the light beam onto the photosensitive drum 92. The light scanning mechanism 96 scans the light beam spot on the photosensitive drum 92 in a direction parallel to its rotational axis X. The photosensitive drum 92 rotates about the rotational axis while being irradiated with the light beam scanned by the light scanning unit 90. Accordingly, the photosensitive drum 92 is formed with a latent image corresponding to the electrical image signals. The latent image is developed into a visible image by a developing unit (not shown in the drawing) and is transferred to an output medium such as a sheet. Thus, the sheet is formed an image the same as that of the original.
As described above, the conventional electrophotographic image recording apparatus requires the two separate light sources 82 and 94 for the image reading portion 81 and the light scanning portion 90. Especially, in the case where the image receiving element 80 is constructed from the contact type image sensor, because the contact type image sensor is expensive, the entire apparatus may not be manufactured with low cost. In the case where the image receiving element 80 is constructed from the CCD image sensor, various optical parts such as a converging lens must be mounted between the original stand 86 and the CCD image sensor. In this case, the entire apparatus becomes expensive as well as large.